Effects of high dietary zinc intake on rumen fermentation, haemotological and biochemical parameters in ruminants animals

This study was performed in order to determine effects of diet containing high zinc on differences in rumen and blood parameters, live weight and oxidant-antioxidant balance in goats. In this study, twenty four male Angora goats, 12 months of age, and weighing approximately 35 kg were divided into four groups as: control group (C) fed with basal diet containing 31.76 ppm Zn, experimental group1 (500) fed with basal diet supplemented 500 ppm Zn, experimental group 2 (750) fed with basal diet supplemented 750 ppm Zn and experimental group 3 (1000) fed with basal diet supplemented 1000 ppm Zn. The investigation was started after a 15 days adjustment period and lasted 30 days. On days 15 and 30 of the study, the blood and rumen samples were taken from animals and weighed. While pH and ammonia levels, protozoon numbers, Zn, Fe and Cu concentrations were determined in rumen contents, red blood cell counters (RBC), hemoglobine, haematocrite level, white blood cell counters (WBC) and their differenciation ratios, plasma cholesterol, glucose and urea nitrogen, Zn, Fe and Cu concentrations, total and free T3 and T4, leptin and insulin levels were measured in the blood samples. There were no differences for body weight and ruminal pH between the groups. Ruminal ammonia and protozoal numbers were decreased (p<0,01) by high zinc supplementations. Rumen Zn concentration increased in the goats fed with high zinc, whereas there was no difference in rumen Fe and Cu concentration amoung treatments, except for 1000 ppm supplementation. RBC and hemoglobin levels decreased significantly (p<0,05) in the control group goats on the fifteenth day than on the thirtieth day but there were no effects of zinc supplementations. High Zn supplementation to diet had not an effect on WBC and hematocrite levels in the goats. High zinc supplementation to diet increased plasma urea nitrogen, GSH and Zn concentrations but decreased leptin concentration and lipid peroxidation. There were no differences in other blood parameters amoung treatments. High zinc supplementation to diet increased the liver Zn and Fe concentrations and mohair Fe levels but decreased the kidney Cu concentrations. As a result, we concluded that the goats can tolerate the supplementation of high zinc to diet.